1. Field of the Invention
This invention relates generally to an electrophotographic apparatus and more particularly to improvements of a roller for use in a liquid developing device for developing an electrostatic latent image and in a rinsing device for rinsing a developer.
2. Description of the Prior Art
Heretofore, liquid developing devices for electrophotography have been classified into two types of systems. One is a system for immersing an electrostatic recording paper or recorder such as a photosensitive member or the like formed with an electrostatic latent image thereon in a developing liquid. The other is a system for contacting a developing roller adhered with a developing liquid to a recording medium formed with an electrostatic latent image. In the so-called wet type developing device of the latter type employing a developing roller such as described in Japanese Patent Publication No. 18,993/1965 and U.S. Pat. No. 3,500,793, grooves are formed on the surface of a developing roller or yarn is wound around the roller to enhance the carrying effect of developing liquid.
Although the conventional developing roller of the latter type achieves considerable carrying effect of the developer, it is almost impossible to uniformly contact the respective portions of the developing roller, which is rotating with respect to the electrostatic latent image surface of the moving recording medium, so as to always maintain the developing electrode effect uniform. Accordingly, it has been very difficult to obtain preferable pictures of good contrast.
Moreover, there are other commonly known problems in the conventional liquid developing system. If, for example, the toner concentration of the developer used is increased, adherence of the toner to the non-electrostatic image portion of the recording medium is increased and the fogging density is simultaneously increased. In color copying, where the developing treatments are repeated several times, the effect of fogging density becomes large. New developments of this technique are, therefore, desirable since the prevalence of electrophotographic developing devices of this type has increased.